Ian Cobain, Paul Lewis and Amelia Gentleman are longlisted for the journalism prize, while David Smith is nominated for his blog from Africa.

Guardian writer Andy Beckett has also been nominated in the book category for When the Lights Went Out, about British politics in the 1970s.

In the journalism category, the Guardian trio join the Mail on Sunday's Peter Hitchens, nominated for the third time in four years, and the Independent and Independent on Sunday's Hamish McCrae and Robert Verkaik.

Gideon Rachman from the Financial Times and Sky News's Tim Marshall also make the list for the blog prize.

Last year the blog prize went to anonymous policeman Jack Night, who was later exposed by the Times as Richard Horton. He becomes a judge this year.

Two public servants writing under pseudonyms have also been longlisted for this year's blog prize – policewoman PC Ellie Bloggs and social worker Winston Smith.

"This year's longlist shows a distinct trend towards reportage and investigative journalism, [with] notable scoops including Ian Cobain on torture, Paul Lewis on policing and the G20 and Cathy Newman with various UK politics stories," said the Orwell Prize organisers.

"Peter Hitchens is longlisted for the third time in four years, while the Economist's Moscow Bureau Chief, Arkady Ostrovsky, is longlisted for a second consecutive year. Mary Riddell was previously shortlisted in 2008."

Due to the high standards of entries in both the journalism and blogs categories, there have been 14 nominees in both categories instead of the usual 12, the organisers added.

This article was amended on 26 March. It originally omitted Andy Beckett from the count of Guardian journalists; this has been corrected.